Amplifier for telephonic transmitters



H. T. DALE.

AMPLIFIER FOR TELEPHONIC TRANSMITTERS. APPLICATION FILED MAR. 31.1919.

1,378,940. Patented May'24, 1921.

HARRY T. DALE, OFNEWYORK, N. Y.

AMPLIFIER FOR TELEPHQNIC TRANSMITTERS.

Specification of Letters Patent. Patented lllay 24, 1921.

Application filed March 31, 1919. Serial No. 286,274.

To all whom it may concern.-

Be it known that I, HARRY T. DALE, a citizen of the United States, and aresident of New York city, borough'of Manhattan, in the county and Stateof New York, have invented certain new and useful Improvements inAmplifiers for Telephonic Transmitters, of which the following is afull, clear, and exact description. V

Among the principal objects which the present invention has in view are:to perfect the transmission of audible sound waves to the diaphragm ofan electric transmitter; to intensify the said sound waves; to avoidoutside disturbances; to collect sound waves over a large area andconcentrate the same upon the center of the recording disk; and toprovide an attachment for the usual transmitter used in the mechanicalaids for the deaf, whereby the sound intensity may be 7 augmented.

Drawings.

Description.

The amplifier is intended primarily for use in conjunction with thetransmitters of instruments used as aids for the deaf, and generallyknown in the trade by the name of audiphones. 7

As shown in Fig. 3 of the drawings, the transmitter indicated by thenumeral 12 has a cover cap 13. This cap usually presses.

upon a gasket which holds the diaphragm of the transmitter in service. Ashoulder 14 is formed on the cover 13. This shoulder is taken advantageof when using the present amplifier, the wall 8 of the amplifier beingrabbeted to form a seat 15 which rests upon the shoulder 14. Arelatively thin gripping section 9 is thus formed. The section 9 isemployed to frictionally grip the side or perimeter of the transmitter12. I

The amplifier is preferably constructed of hard rubber which issufliciently resilient where the thin portion is formed to accommodatedifi'erent characters of transmitters and variations in the standardtypes.

The wall 8 of the amplifier is made thick to avoid inherent vibration-At the upper edge of the wall 8, the material is shaped to form theinturned funnel-like member 10. It will be noted that the edge of themember 10 is made very thin toward the center and particularly adjacentthe opening 11. The opening 11 registers with the perforated centralportion of the cover 13. The wall terminating in the member 10 operatesto concentrate the sound waves for delivery through the opening 11. Themember 10 is depressed as best shown in Fig. 3 of the drawings to forman annular chamber 16.

Due to the depression of the thin wall of the member 10 at the opening11, the air which is contained in the chamber 16 is substantiallytrapped. When the sound waves are delivered into the chamber or into thespace between the outer wall of the amplifier 8 and theouter wall of thecover 13, the body of air in the chamber 16 is vibrated. Due to theshape of the inner surface of the said chamber, these vibrations arefirst deflected from the inner surface of the wall 8 to the over-hanginginner surface of the wall 10 to be thereby deflected toward the centralperforated portion of the cover 13. The vibration of the air containedin the chamber 16 multiplies the effect on the diaphragm when deliveredthrough the area covered by the perforations in the cover 13, directlyover the center of said diaphragm.

' As a result of this amplification of the vibration the sound waves areintensified and the diaphragm is more violently operated upon with theresult that the microphone or transmitter 12 delivers a correspondingelectric oscillation to the telephonic system in- While I prefer tomanufacture the amplifier from hard rubber, it will be understood that avariety of materials may be used.

To assist the gripping portion 9 in accommodating a variety of sizes ofthe transmitter 12, I sometimes provide the edge 9 with longitudinalslits 17 as best seen in Fig. 2 of the drawings. This separation of thethin having an annular rigid portion adjacent 10 portion 9, permitsslight expansion thereof. and integral With saidannular wall; and a thinvibrant portion integrally formed with said annular portion adjacent thesaid open- As an article of manufacture, a removable ing for forming asensitive vibrant member slip cover for a telephonic transmitter, saidfor amplifying the acoustic vibration under 15 cover having a relativelythick annular Wall said top. and a top, the center whereof is pierced toI I form a single contracted opening, said top HARRY T. DALE.

Claim.

